急性一氧化碳中毒大鼠脑内Bax基因表达初步探讨

Expression of Bax gene in the brains of rats after acute carbon monoxide poisoning

目的 :通过急性一氧化碳中毒后大鼠脑内细胞凋亡相关基因Bax表达的研究 ,探讨一氧化碳中毒致脑损伤的机制 ,为进一步研究把相应的基因治疗引入一氧化碳中毒后迟发脑病的防治提供依据。方法 :体重 15 0～ 2 5 0g的雄性SD大鼠 ,吸入 2 0 0 0～ 30 0 0ppm的一氧化碳气6 0min ,测定染毒后即刻和处死时碳氧血红蛋白 (COHb)水平 ,断头取脑 ,分离大小脑 ,分别以网搓法制成单细胞悬液 ,经抗体结合荧光 ,应用流式细胞仪检测表示中毒后不同时间大小脑内Bax基因的表达量的平均荧光强度。结果 :大鼠大小脑均表现为中毒后即刻Bax表达有所增高 ,中毒后 2 4h达高峰 ,中毒后 7d恢复到正常水平。结论 :急性一氧化碳中毒可诱发脑内Bax基因的表达 ,Bax基因表达可能是急性一氧化碳中毒致脑损伤的病理机制之一。

Objective:The purpose of the study was to evaluate the expression of the apoptosis-associated gene,Bax,in the brains of rats after exposure to carbon monoxide.Methods:Thirty male SD rats,weighing 150～250g,were randomly divided into 6 groups.After exposure to 2000～3000ppm of CO for 60 minutes,the blood COHb levels of the rats were measured by co-oxmeter immediately after exposure and at the time of execution-24 hours、72 hours、7 days after the exposure.The cell suspensions were prepared from the cerebrum and the cerebellum of each rat.The expressed gene protein,Bax,in the cytoplasm of the cerebral and cerebellar cells was probed with fluorescence-FITC by combinding with antibodies,and then measured by flow cytometric method.The extent of the expression of the gene Bax was showed by mean fluorescence intensity(MFI).The data was analyzed by q-test.Results:COHb levels increased abruptly just after the CO exposure and returned to normal 24 hours after it,and there was no statistic difference among the COHb levels of CO exposed groups at the time just after the exposure.The basic levels of Bax(MFI) in cerebrum and cerebellum were 3262±484 and 2114±269 respectively.The expression of Bax in both cerebrum and cerebellum increased after CO exposure,reached the peak levels at 24 hours(4623±457 and 3582±379 respectively,P<001),and returned to normal on day 7.Conclusion:Acute carbon monoxide poisoning can induce the expression of gene Bax,which may be one of the mechanisms of brain damage caused by carbon monoxide poisoning.